Bit of an update:
That Alvarez MD-90CE sold so ...
I did check on one GAD-50 and the serial number showed it was made in 2008 IIRC. It has also been sold.
I checked on another GAD-50 and the seller said the shop discovered it had a defect so the price was dropped about 30 percent and was offered on a "no returns" basis. I did not want to buy a guitar online that way. It also has been sold, I imagine to somebody locally.
That GAD-50 with the "impossible" serial number is still available. I contacted the seller who looked at the number again and said it appears to be as he said, beginning with "19" but he concluded it may be instead "13" or "18" or "10" because he said the numerals were so faded out.
So that now is my only option in my price range. Actually the more I thought about it I was drawn to the Alvarez MD-90 because it has an Englemann spruce top which may suit my style of playing better. I don't play fingerstyle but I'm a soft player and I appreciate the nuances of sounds. On the other side of the sonic spectrum, I played a Recording King RD-328 that has an Adirondack spruce top. It was very loud but a little harsh. I also understand Adi tops take the longest time to break in and mellow out a bit. When I was going to acoustic jams, however, I would have loved to have had a loud guitar because, as I think I said, my mid-70s D-55 I thought was overbuilt and it was a very quiet guitar, lovely at low volumes but just not made for mid-sized or larger jams.
I do welcome any other suggestions. Maybe there is some other guitar with the specs and the price that would be OK for me.